This revised version of the paper by Rupa Chanda is part of a series of research papers prepared for the Working Group on Health and International Economy of the Commission on Macroeconomics and Health (CMH). The Commission was set up in January, 2000, by the Director General, World Health Organisation, under the Chairmanship of Prof. Jeffrey Sachs. As a member of the CMH and Co-chairperson of this Working Group, I have had the privilege of commissioning research papers on issues of importance for health and the international economy. The paper provides an overview of the nature of international trade in health services and the lessons that can be learnt from the national, regional, and multilateral experience in this context. The study discusses the various ways in which health services can be traded, the main global players in this trade, and the positive as well as negative implications of this trade for equity, efficiency, quality, and access to health services. It also outlines some of the main barriers constraining trade in health services. While some of these barriers are imposed for reasons for public policy and consumer interest, others are clearly protectionist.